Intake filter for an internal combustion engine of a motor vehicle

ABSTRACT

An intake filter for an internal combustion engine for a motor vehicle including an unfiltered air intake region, a filter medium and a filtered air conduit, in which the unfiltered air intake region is arranged beneath the engine hood of the motor vehicle and is attached to the engine hood. The filter medium is tubular body which has a porosity that ensures a sufficient filtration of the intake air for the internal combustion engine.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of international patent applicationno. PCT/EP2005/051486, filed Mar. 31, 2005 designating the United Statesof America and published in German on Oct. 13, 2005 as WO 2005/095783,the entire disclosure of which is incorporated herein by reference.Priority is claimed based on Federal Republic of Germany patentapplication no. DE 10 2004 016546.7, filed Mar. 31, 2004.

BACKGROUND OF THE INVENTION

The invention relates to an intake filter for an internal combustionengine of a vehicle comprising a dirty air intake area, a filter mediumand a clean air pipe, wherein the dirty air intake area is disposed onthe underside of the engine hood of the vehicle and is connectedthereto.

U.S. Pat. No. 4,932,490 discloses a vehicle with an internal combustionengine. To supply the intake air for the internal combustion engine, anunfiltered air passage is provided on the engine hood to receive the airflowing in from the front of the vehicle. This unfiltered air passageleads to a filter housing in which is disposed a filter element forfiltering the dirty air. The clean, filtered air flows through afiltered air passage disposed on the engine hood side to a transfer unitfrom where it is guided to the internal combustion engine through aflexible hose. When the engine hood is opened, the flexible hose isseparated from the clean air passage. The air filter is mounted to theengine hood and can be replaced as needed. To mount the air filter, acorresponding housing is provided, which can be opened.

One drawback of this device is that the housing of the air filter is arigid structure. Similarly, the unfiltered air- and filteredair-carrying members are specially configured sheet metal parts that aremounted to the engine hood. They cause a stiffening of the engine hoodin an area that should be relatively flexible for safety reasons. Inaddition, a special housing is required for the air filter element,which adds a not inconsiderable amount of weight to the engine hood.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide an improvedinternal combustion engine air filter which is mounted to the enginehood.

Another object of the invention is to provide a hood-mounted intakefilter for an internal combustion engine which does not impair thefunction of the engine hood or require a special housing.

These and other objects are achieved in accordance with the presentinvention by providing an intake filter for an internal combustionengine of a motor vehicle comprising an unfiltered air intake area, afilter medium, and a filtered air duct, in which the unfiltered airintake area is disposed on the underside of the engine hood of thevehicle and is attached to the engine hood; and in which the filtermedium comprises a tubular body having a porosity such that adequatefiltering of the intake air for the internal combustion engine isensured.

Thus, in accordance with the present invention, the filter medium isformed of a tubular body that has a porosity sufficient to ensureadequate filtering of the intake air for the internal combustion engine.

The present invention is advantageous in that the filter system can beaccommodated within the engine compartment of a vehicle in aspace-saving manner. In particular, the engine hood of the vehicle andthe space between the engine hood and the engine can advantageously beused to mount the relatively soft element or elements of a tubularfilter body. Due to the relatively large size of the area available, aplurality of tubular elements may be arranged in parallel. Theconfiguration can be adapted to the engine hood structure.

In one embodiment of the invention the proposed tubular body comprises atubular filter having a diameter ranging from 40 to 80 mm. A tubularfilter of this type can be formed of, for example, a nonwoven body, thenonwoven material of which has filtering properties.

It is of course also possible, according to a further embodiment of theinvention, to provide the tubular body with a pleated geometry tofacilitate a curved installation. The filter element is pleated, forexample, by forming a plurality of parallel folds arranged side by side,which extend perpendicularly to the longitudinal axis of the filter.

In accordance with another embodiment of the invention the filter mediumis provided on the filtered air side with a resilient support member.This support member may, in particular, comprise a helically extendingsupport wire or a correspondingly configured support grid. Of course, asupport member can also be formed of polymeric material as well as ofmetal.

To prevent the intake of hot engine exhaust, in one advantageousembodiment of the invention, the tubular body may be provided with acover. This cover ensures that the fresh air to be drawn in flows in atdefined points, as for example in the upper area of the radiator grille,and is supplied to the intake filter. The cover also may have acousticproperties, so that it helps reduce the intake noise of the internalcombustion engine.

According to another embodiment, the tubular body is a wound filterelement which comprises a plurality of groove-like hollow channels withadjacent channels open and closed at alternate ends. Wound filters ofthis type have the advantage that they have a very short overall lengthand a large effective filter surface. They are also compact and easy toreplace.

These and other features of preferred embodiments of the invention, inaddition to being set forth in the claims, are also disclosed in thespecification and/or the drawings, and the individual features each maybe implemented in embodiments of the invention either alone or in theform of subcombinations of two or more features and can be applied toother fields of use and may constitute advantageous, separatelyprotectable constructions for which protection is also claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in further detail hereinafter withreference to illustrative preferred embodiments shown in theaccompanying drawing figures, in which:

FIG. 1 is a schematic view of the engine compartment of an automobilewith hood open;

FIG. 2 shows the construction depicted in FIG. 1 with a modified filtervariant;

FIG. 3 is a perspective view of a wound filter element for installationin an engine hood;

FIG. 4 is perspective view of a variant of a wound filter element foroptimal adaptation to the structure of an engine hood;

FIG. 5 is a schematic representation of an engine compartment of a motorvehicle;

FIG. 6 is perspective representation of a pleated filter element, andFIG. 7 is a front elevational detail view of the device illustrated inFIG. 5.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 schematically illustrates the engine 10 of a motor vehicle. Onthis engine 10, there is an opening 11 through which the intake airflows in and from where it is distributed to the individual cylinders ofthe engine. An engine hood 13 is arranged on top of the enginecompartment 12. In FIG. 1 the engine hood is shown open so that theunderside of the hood is visible. On the underside of hood 13 there is aplenum chamber 14 with a filtered air opening 15. This plenum chamber inturn has openings to the outside, which communicate with tubular filterelements (tubular filters 16, 17, 18, 19, 20). These tubular filterseach have a round or oval cross section and are likewise depicted onlyschematically. In addition to the tubular filters, resonance chambers 21and 22 are provided, which communicate with the plenum chamber 14through openings and which are appropriately configured to dampen theintake air noise. The tubular filters and the resonance chambers arecovered relative to the engine by a substantially airtight cover 23. Inthe drawing the cover is merely indicated by a broken line. This coveris open toward the front of the vehicle and toward the front of theengine hood, so that fresh air can flow into the filter area from thefront, i.e., from the front of the vehicle, as indicated by arrows 24.This fresh air is cleaned by the tubular filters and made available tothe internal combustion engine.

A connection between the clean air opening 15 and the opening 11 for theintake air on the engine 10 is established by closing the engine hood.If desired, both openings may be permanently connected by a flexibleconnecting hose 25. It is also possible to use suitable interengagingconnecting members to produce the elastic connection, which is releasedwhen the engine hood is opened, but this requires that the opening 11 beclosed when the engine hood is open. Closure of opening 11 can beaccomplished, for example, by a suitable diaphragm or flap over theopening.

FIG. 2 shows an alternate embodiment using a flexible tubular filter 26connected to the intake plenum 14 in place of the static tubularfilters. In this figure, components corresponding to those depicted inFIG. 1 are identified by the same reference numerals. The tubular filter26 is formed of a nonwoven web or paper material with filteringproperties. The filter medium itself has a plurality of parallel pleatsarranged side by side and extending perpendicularly to the longitudinalaxis of the filter. This makes possible a flexible installation of thefilter medium adaptable to the structure of the engine hood. Of course,many different types of installation are feasible here. For high volumeengines, in particular, it is possible to provide a correspondinglylarge active filtering surface.

Figure shows the filter medium as a wound filter element. This woundfilter consists of a first, flat filter web 27 onto which is placed asecond, corrugated web 28. Corrugated web 28 is glued to the flat web 27by a bead of adhesive 29 on one side of the filter element. Duringwinding, a bead of adhesive 30 is applied to the opposite side to jointhe corrugated web 28 to the previously wound flat web 27. This createschannels 31 which are open at one end so that air can enter. The aircannot escape on the opposite end, however, because the opposite end isclosed by the adhesive. Instead, the air must pass through thecorrugated filtering web, whereby it is filtered, into an adjacentchannel which is open at the opposite end so that the now filtered aircan exit from the opposite side. A wound filter of this type can, ofcourse, also have an oval shape. Alternatively, the flat and corrugatedlayers can be stacked to form a cube as shown in FIG. 4.

FIG. 4 also illustrates the alternately closed openings of theindividual channels. The unfiltered air enters the channels in thedirection indicated by arrows 32, flows through walls of filter materialseparating adjacent channels as indicated by arrows 33, and leaves thefilter element clean as indicated by arrows 34.

FIG. 5 is a schematic view of the front end of a vehicle, including theinternal combustion engine 40, which is mounted above a floor panel 41.A cooling system 42 is provided in front of the internal combustionengine. A bumper 43 is located in front of the cooling system 42. Theengine compartment is closed by the engine hood 44. A plenum chamber 45is mounted to the underside of the engine hood. An intake manifold 47extends from this plenum chamber 45 through a connecting flange 46 tothe internal combustion engine 40. At least one intake air duct 48 isassociated with the plenum chamber 45. Each intake air passage 48 islikewise disposed directly on the underside of the engine hood 44 andextends to the air inlet 49. Air inlet 49 is disposed in the area of thefront end of the internal combustion engine. A tubular filter 50 isdisposed inside intake air passage 48 and extends from the air inlet 49over a specific length of the intake air passage.

To reduce intake noise at the air inlet 49, a flap valve 51 may beprovided in the intake air passage 48. This reduces the cross-section ofthe passage depending on the required air volume and thereby preventssound radiation of the intake noise of the internal combustion engine.It is also possible to dispose this flap valve directly at the air inlet49, optionally in front of the tubular filter 50. Below the intake airpassage 48, a sound absorbing insulating mat 52 is provided, whichsimultaneously acts as the lining for a plurality of intake airpassages. If the engine hood 44 can be opened, the intake manifold 47 isa pipe that is flexible over its length. This flexibility is obtained,for example, by pleating or by a telescopic construction. If the enginehood can be removed only for maintenance purposes, the intake manifold47 can be made rigid. In this case, the intake manifold 47 must bedetached at the connecting flange 46. In these cases, the connectionbetween intake manifold 47 and connecting flange 46 can be a plug-inconnection.

FIG. 6 is a detail view of a tubular filter 50 which is pleated inlongitudinal direction and disposed in a closed intake air passage 48.Unfiltered air flows into the interior of the tubular filter 50. This ofcourse requires the hatched area 52 to be sealed, which is accomplishedby a correspondingly configured flange. The air to be cleaned flowsoutwardly within the intake air passage 48 into the clean air area andthen flows through the intake air passage to the plenum chamber 45.

FIG. 7 is a front elevational detail view of a vehicle with theindividual intake air passages 48 a-d disposed in the area of the airinlet. It may be seen here that four individual intake air passages runto the plenum chamber. The advantage of individual intake air passagesis that they can take different paths and can also detour aroundstructures of the engine hood if necessary. At the entry of the intakeair passages into the plenum chamber, the cross section abruptlychanges. This abrupt change in cross section is necessary to improve theintake acoustics, i.e., to reflect sound waves. If the intake airpassages are disposed on the underside of the engine hood it isadvantageous to seal the openings relative to the engine compartment sothat no hot air is drawn in, but fresh air from the area of the frontend can be supplied in any case.

The foregoing description and examples have been set forth merely toillustrate the invention and are not intended to be limiting. Sincemodifications of the described embodiments incorporating the spirit andsubstance of the invention may occur to persons skilled in the art, theinvention should be construed broadly to include all variations withinthe scope of the appended claims and equivalents thereof.

What is claimed is:
 1. An intake filter for an internal combustionengine of a motor vehicle, said filter comprising an unfiltered airintake area, a filter medium, and a filtered air duct, wherein theunfiltered air intake area is disposed on the underside of the enginehood of the vehicle and is attached to the engine hood; wherein thefilter medium comprises a tubular body mounted to and moving with theengine hood, the filter medium having a porosity such that adequatefiltering of the intake air for the internal combustion engine isensured; wherein the tubular body has a pleated geometry thatfacilitates a curved installation; wherein the tubular body is providedon the side opposite the engine hood with an elastic, resilient,substantially air-tight cover, said air-tight cover open toward thefront of the vehicle and toward the front of the engine hood to draw inair; and wherein at least two intake air passages are provided in whichthe filter medium is arranged, each of said intake air passagesextending directly under the engine hood between said engine hood andsaid elastic air-tight cover and opening into a common plenum chamber.2. An intake filter according to claim 1, wherein the tubular body is atubular filter having a diameter in the range from 40 to 80 mm.
 3. Anintake filter according to claim 1, wherein the filter medium has aplurality of side-by-side pleats arranged parallel to each other andperpendicular to the longitudinal axis of the tubular filter.
 4. Anintake filter according to claim 1, wherein the filter medium includes aresilient support element on at least one of the unfiltered air side andthe filtered air side of the filter medium.
 5. An intake filteraccording to claim 4, wherein said resilient support element comprises ahelical support wire.
 6. An intake filter according to claim 1, whereinthe filter medium comprises a pleated structure in which the pleatsextend longitudinally along the tubular body.
 7. An intake filteraccording to claim 1, wherein each of said at least two intake airpassages is provided with a filter medium in the form of a tubular body.8. An intake filter according to claim 1, wherein a flap valve isarranged in the intake air passage in the vicinity of the air inletwhich opens or closes depending on the air throughput.
 9. An intakefilter according to claim 1, wherein an intake manifold is provided forsupplying filtered air from the plenum chamber to the internalcombustion engine, said intake manifold being connected by an openableconnecting nipple or by a flexible or telescopically movable hose orduct to the plenum chamber.
 10. An intake filter according to claim 1,wherein the tubular body is a wound filter, which comprises a pluralityof groove-shaped hollow channels, wherein adjacent channels areseparated by a wall having filtering properties, and each channel isclosed at one end, with adjacent channels being closed at alternatingends such that unfiltered air entering an open channel at one end of thefilter must flow through a wall into an adjacent channel in order toexit the filter at the other end of the filter, whereby the air isfiltered.
 11. The intake filter according to claim 1, wherein the enginehood defines a surface of the unfiltered air intake area in cooperationwith an airtight cover of the unfiltered air intake area.
 12. The intakefilter according to claim 1, wherein the engine hood defines a surfaceof a plenum chamber in fluid communication with the filtered air duct.13. The intake filter according to claim 1, wherein the filter medium ismovable with the engine hood when the engine hood is opened.